Improvement in the manufacture of pigments containing zinc and lead



UNITED STATES PATENT OFFICE.

FRANKLIN OSGOOD, OF NEW YORK, N. Y.

IMPROVEMENT IN THE MANUFACTURE OF PIGMENTS CONTAINING ZINCAND LEAD.

Specification forming part of Letters Patent No. 137,474, dated Aplil 1,1873; application filed March 21, 1873.

To all whom it may concern:

Be it known that I, FRANKLIN Osooon, of the city, county, and State ofNew York, have invented a new and useful Improvement in the Manufactureof Pigments containing Zinc and Lead; and I do hereby declare thefollowing to be a full and exact description of the same.

Heretofore pigments containing zinc and lead have been manufactured intwo ways: First, by a mechanical mixture of materials known as oxide ofzinc and the white lead of commerce; second, by treatment of ores ofzinc containing lead, or ores of lead containing zinc, by a fire processin a furnace, whereby a greater or less proportion of the lead wascarried over in a vaporized form and combined with the oxides of zinc.This species of pigment has been termed in trade zinc-lead; and for itsmanufacture it has been customary to use solely the sulphurets of zinccontaining lead found in mines and known as zinc-blend, black-jack, orother local or mineralogic term.

The difficulties of this operation have been the irregular proportion oflead in the ore, and the danger in the roasting of forming salts whichwere not oxidizable except at a heat higher than would flux the metallead. From these causes the product was variable in quality, and theyield in quantity. Further, it is well known that large quantities ofzinc metal are used in the process of galvanizing and other manufacturesof the arts, and that from these processes and manufactures is resultantlarge amounts of dross and skimmings, which have heretofore been, in agreat measure, a loss to the manufacturer, and that many attempts havebeen made to utilize these said skimmings or dross in the manufacture ofpigments without producing a perfectly oxidized mate, rial, or one fullyrecognized as marketable.

Therefore, having made a pigment containin g zinc and lead by anentirely new process, and having succeeded in utilizing these skimmingsor dross, and making therefrom a thoroughly oxidized material containingzinc and lead, and which is fully equal or superior to any zinc-leadever before made, I will now proceed to describe my method of carryingthe same into effect.

I take any of the known ores of zinc and roast the same so as toseparate any acid, whether they be sulphurets, sulphates, carbonates, orchlorides; then introduce them into a suitable furnace, such as areverberatory, that known as the Wetherell or other form answering mypurpose, mixing with them the usual quantity of coal-dust; or, bypreference, I take the zinc dross or skimmin gs, if the latter be knownas ammoniacal, then first depriving them of all trace of such alkali;then I mix with coal and introduce into the furnace in the same manneras with the roasted ore. In another furnace I charge, in a similarmanner, ores of lead or lead dross, or a salt of lead, mixing in coal inlike manner; or, if preferred, I mix these metallic materials and thecoal allvin one furnace. In either case, if fire has not already beenkindled it is now applied to a greater or less degree. As the heat risesthe vaporized metals pass upward and are drawn through flues by anexhaust. The mixed vapors of lead and zinc unite and form acombination,which, being condensedin chambers or bags in chambersadapted for that purpose, forms the material which is known to the tradeas zinc-lead.

It is seen that in this process no particular form of furnace isrequired so long as the vapors of the two metals are formed; neither isit essential that the lead and zinc substances should be mixed in thesame furnace; but itis positively necessary that their vapors shouldcome together under the influence of heat and air; hence it is seen thatthe material Iproduce is not a new one, except in its superior quality,and a part of the materials from which it is produced have never beenheretofore used for the purpose.

Having thus described my invention, what I claim, and desire to secureby Letters Patout is- I l. The process herein described for producingzinc-lead, the same consisting in passing the vapors of zinc and leadproduced by heating the above-mentioned compounds through a flue bymeans of a pressure of air-blast, as set forth.

2. The process of producing zinc-lead by the mixture of an ore and ametal, or the dross of ameta-l, in a furnace, substantially in themanner described, so that when vaporized by heat inoniaeal skimmings,for the purpose of comthey will pass over through flues into chambiningthe same with lead'or ores for the probers and condense into a materialknown as duction of the pigment known as zinc-lead.

zine-lead, having formed a complete union at FRANKLIN OSGOOD. some pointof their passage. Witnesses:

3. The method described for the utilization HENRY E. OOLTON,

of dross or skimmings of zinc known as mn- CLARENCE GARY.

